Expression of Toll-like receptors 7, 8, and 9 in primary Sjögren's syndrome

ObjectiveThe objective of this study was to investigate the level of Toll-like receptors (TLRs) 7, 8, and 9 in peripheral mononuclear blood cells (PMBCs) from patients with primary Sjögren's syndrome (pSS) and whether TLR7 and 9 exist in the parotid glands of pSS patients.MethodsTLR7, 8, and 9 mRNA levels in PMBC from 37 pSS patients and 24 controls were determined using real-time polymerase chain reaction. TLR7- and TLR9-positive cells in parotid glands from 20 pSS patients and 10 controls were observed using immunofluorescence and immunohistochemistry, respectively. Statistical analysis was performed by Student t test.ResultsTLR7 and TLR9 mRNA levels were 2.17- and 2.33-fold higher in pSS patients than control subjects, respectively (P < .05), whereas TLR8 levels were not. TLR7- and TLR9-positive cells of the pSS group were localized in the epithelial islands, lymphocytes, and ductal epithelial cells of the parotid glands and were more abundant than the TLR7- and TLR9-positive cells that were only localized to the ductal epithelial cells of parotid glands (P < .05).ConclusionTLR7 and TLR9 mRNA levels are up-regulated in the PMBC of pSS patients, and TLR7- and TLR9-positive cells exist in the epithelial islands, lymphocytes, and ductal epithelial cells of the parotid glands of individuals affected by pSS, but are limited to the ductal epithelial cells of controls.